Piezoelectric loads, e.g. piezoelectric elements, are normally powered by a charge pump or current amplifier. There are several challenges involved in connection with controlling charging of piezoelectric loads, and capacitive loads in general. One challenge relates to controlling the piezoelectric load in order to control the elongation or contraction of the piezoelectric load.
Control of the elongation or contraction of a piezoelectric load is important for applications where the piezoelectric load is used for actuating deformable lenses, e.g. lenses which are used for imaging purposes. In order to obtain a high image quality, e.g. sharpness of the image, the lens must be deformed predictably to obtain a desired optical power.
Accordingly, there is a need to improve control of piezoelectric loads, e.g. piezoelectric loads for actuating deformable lenses.
There is also a need for obtaining information about the state, e.g. health state or change of piezoelectric characteristics, of the piezoelectric load due to aging.